Boom

a Dutch word akin to beam. In a ship a boom is a long pole or a spar, jutting out from a mast to extend the lower edge of a sail. In Nelson's battleships the boom was from thirty to fifty feet in length, and was from six to fifteen inches in diameter at the larger end. In logging, a boom is a chain of logs fastened end to end, stretched across a river, or other body of water, to confine floating timber. When lumbermen desire to tow logs across a lake, they unload them on the ice and surround them with a boom. The boom is then chained to a tree on the shore. After the ice has gone in the spring the boom is loosened from the shore. With its contents it may then be towed by a steam launch or dragged with a cable and windlass. When a number of sawmills are located near together, booms, enclosures, or slips are made by long lines of logs lying in the water parallel to each other. The logs for each mill are driven in at the upper end of the slip and float downward to the place where they are wanted. "Boom scale" is a lumberman's expression for the value of the logs safely in the boom.